I am recently engaged, and my fiance gave me a ring that has been in his family for 100+ years (originally worn by his grandmother or great-grandmother). I am extremely fascinated by this ring, and I'd love to know the origin of the ring I will wear for the rest of my life (it's a stacking ring meant to pair with the wedding band, as you can see below).
His mother does not know any other information about the ring, but his family is originally from Mexico, so the ring could be of American, Mexican, or some other Central American origin. I believe the mark below (third picture) says "RCG 14K", but I have not found a mark on the website that resembles it using "R", "C", or "G" as starting points for my search.
I'd appreciate any help finding this ring's origin, thank you for your time.